Apparatus and method for gaining operational access to a pressure vessel

ABSTRACT

The disclosure includes embodiments of an apparatus and a method for gaining operational access to a pressure vessel. In one embodiment, an apparatus is described that is shaped and formed to replace a conventional manway portal cover of a pressure vessel. The apparatus includes an aperture that allows for an object such as, for example, a monitoring device to be attached along the aperture, thereby allowing for increased access to the interior of the pressure vessel during operation of the pressure vessel without the necessity of creating a new aperture in the pressure vessel itself or destroying the conventional manway portal cover. A method is also disclosed for using the described embodiments of the apparatus.

FIELD

This disclosure relates to the field of pressure vessels. More particularly, this disclosure relates to an apparatus for safely, efficiently, and relatively cheaply gaining operational access to pressure vessels.

BACKGROUND

Pressure vessels are used in a variety of industries for a variety of purposes. By their nature, pressure vessels hold contents under pressure, making them potentially dangerous. Because of the potential dangers associated with pressure vessels, the contents in such vessels are often monitored. Such monitoring may include the removal of samples from the interior of a pressure vessel. Other applications than monitoring may similarly require the removal of matter from the interior of a pressure vessel while the pressure vessel is in operation and/or the addition of matter to the interior of the pressure vessel while the pressure vessel is in operation. As monitoring techniques and equipment have improved over the years, the amount of access to the interior of pressure vessels for monitoring and other purposes has increased because modern pressure vessels are typically made with ample access points (e.g., apertures) to the interior of the pressure vessel for housing, for example, modern monitoring equipment. However, many pressure vessels have very long life-spans. Older pressure vessels still in use have fewer, if any, access points built-in for gaining operational access to the interior of such pressure vessels for monitoring or other purposes while the pressure vessel is in operation. For some of these older pressure vessels, a manway portal is all that is available, and such manway portals must be closed while the pressure vessel is in use. As technologies develop that require additional operational access to the interior of pressure vessels, even newer pressure vessels may require additional access points. Thus, there is a need for adding access points to many pressure vessels that are in use today.

Currently, if additional (i.e., new) access points are desired, such access points must be made in the pressure vessels themselves, increasing costly downtime, labor costs, and safety and insurance concerns (particularly with pressure vessels that are used to hold flammable, oxidizable, or other dangerous materials). Many pressure vessels used today have manway portal covers that are pressure and temperature rated under the ASME code—that is, they are certified based on the conditions under which they fail. If, however, an aperture were created in an ASME fail-test rated manway cover after the cover were certified, the manway cover would no longer be reliable because the basis of its rating would be compromised. Thus, creating an access point in a pressure and temperature rated manway portal cover is not a desirable or otherwise viable option.

What is needed, therefore, is a convenient, efficient, and cost-effective way to add access points to pressure vessels that require additional access points to be used for, as an example, in-line monitoring or other activities that need to be accomplished while the pressure vessel is in operation.

SUMMARY

The above and other needs are met by a cover apparatus for providing access to a pressure vessel. In a basic embodiment, the apparatus includes a plate dimensioned to fit through a manway portal of a pressure vessel and to substantially sealingly engage with the pressure vessel so that the plate substantially covers the manway portal from the interior of the pressure vessel, the plate including a first surface, a second surface, an aperture located through the plate, and a plurality of engagement members along the second surface of the plate. The plurality of engagement members are for engaging the apparatus with an attachment member that is capable of holding the second surface of the plate against an inner surface of the pressure vessel at least until the pressure vessel is pressurized. In a related embodiment, the apparatus also includes one or more attachment members for holding the second surface of the plate against the inner surface of the pressure vessel. In a preferred embodiment, the attachment members may be oriented to overlap an outer edge of a collar flange surrounding the pressure vessel, wherein the plate may be held in place substantially covering the manway portal of the pressure vessel by attaching the attachment members to the engagement members and orienting the attachment members such that the attachment members overlap the outer edge of a collar flange surrounding the pressure vessel at two or more points along the outer edge of the collar flange. In a particularly preferred embodiment, the cover apparatus includes a plurality of attachment pockets that extend partially into the plate along the second surface of the plate near the aperture, the plurality of attachment pockets for attaching an object to the plate along the aperture. The aperture is preferably located substantially at the center of the second surface of the plate.

In a preferred embodiment, the plurality of engagement members includes a plurality of extension members extending from the second surface of the plate, each extension member including an aperture. In a particular embodiment, the attachment members include sets of (1) a bolt including a first end and a second end, and (2) a retainer member including an aperture, wherein the apparatus may be attached to a pressure vessel by extending each bolt through the associated aperture of the associated retainer member, orienting the retainer member such that a portion of the retainer member overlaps the outer edge of the collar flange surrounding the manway portal, and attaching the second end of each bolt to the respective apertures of the extension members. Additionally, the cover apparatus may include a plurality of balancing members oriented between the retainer members and the second surface of the plate, wherein the retainer members may be oriented to overlap the balancing members while the retainer members also overlap the outer edge of the collar flange, wherein the balancing members are capable of distributing a force from the retainer member to both the outer edge of the collar flange and the balancing members.

In an alternative embodiment, the plurality of engagement members includes a plurality of attachment ports extending partially into the second surface of the plate. In a particular embodiment, the attachment members include sets of (1) a bolt including a first end and a second end, and (2) a retainer member including an aperture, wherein the apparatus may be attached to a pressure vessel by extending each bolt through the associated aperture of the associated retainer member, orienting each retainer member such that a portion of each retainer member overlaps the outer edge of the collar flange surrounding the manway portal, and attaching the second end of each bolt to the respective attachment ports. Additionally, the cover apparatus may include a plurality of balancing members oriented between the retainer members and the second surface of the plate, wherein the retainer members may be oriented to overlap the balancing members while the attachment members also overlap the outer edge of the collar flange, wherein the balancing members are capable of distributing a force from the retainer member to both the outer edge of the collar flange and the balancing members.

In yet another alternative embodiment, the plurality of engagement members includes a plurality of attachment rods extending orthogonally from the second surface of the plate. In a particular embodiment, the attachment members include sets of (1) a retainer member and (2) a cap member, each retainer member including an aperture, whereby the plate may be attached to a pressure vessel by placing a separate retainer member along each rod such that each rod is exposed through the associated aperture of the associated retaining member, orienting each retainer member such that a portion of each retainer member overlaps the outer edge of the collar flange surrounding the manway portal, and attaching a separate cap member to the end of each respective rod. Preferably, the cap members include threaded nuts and the rods are preferably at least partially threaded. Additionally, the cover apparatus may include a plurality of balancing members oriented between the retainer members and the second surface of the plate, wherein the retainer members may be oriented to overlap the balancing members while the retainer members also overlap the outer edge of the collar flange, wherein the balancing members are capable of distributing a force from the retainer member to both the outer edge of the collar flange and the balancing members.

The disclosure also covers a pressure vessel including any of the embodiments of the cover apparatus described above.

In another aspect, embodiments of the disclosure provide a method for adding a new access aperture to a pressure vessel without the necessity of creating an aperture in the pressure vessel or associated manway portal cover. The method includes the step of providing a cover apparatus for providing access to a pressure vessel, comprising a plate dimensioned to fit through a manway portal of a pressure vessel and to substantially sealingly engage with the pressure vessel so that the plate substantially covers the manway portal from the interior of the pressure vessel, the plate including a first surface, a second surface, an aperture located through the plate, and a plurality of engagement members along the second surface of the plate, the plurality of engagement members for engaging with an attachment member that is capable of holding the second surface of the plate against an inner surface of the pressure vessel at least until the vessel is pressurized. The method further includes the step of inserting the plate through the manway portal of the pressure vessel such that the second surface substantially faces out through the manway portal. The method further includes the step of attaching a plurality of attachment member to the plurality of engagement members such that the manway portal is substantially sealingly obstructed by the cover apparatus. The method may also include a step of orienting the attachment member so that the attachment member overlaps an outer edge of a collar flange surrounding the manway portal of the pressure vessel at two or more locations along the outer edge of the collar flange. Preferably, the method includes the step of attaching an object to the cover apparatus whereby the object is exposed to the interior of the pressure vessel after the manway portal becomes obstructed by the cover apparatus.

Advantages of these and other embodiments of the disclosure discussed herein include an apparatus that may be rapidly swapped with a conventional manway portal cover for the purpose of gaining operational access to a pressure vessel in very little time.

Another advantage of the embodiments disclosed herein includes an apparatus and method that eliminate safety issues and related liability, particularly if the pressure vessel typically contains hazardous materials such as, for example, flammables, corrosives, and/or oxidizers.

Yet another advantage of the embodiments disclosed herein includes a cover apparatus and method that eliminates the expensive labor costs of paying a skilled worker (e.g., a welder) to create an access point in a pressure vessel. The endeavor of gaining operational access to a pressure vessel would be simplified to the substitution of a manway portal cover described herein for a conventional manway portal cover.

Another advantage of the embodiments disclosed herein includes a cover apparatus that is flexible in the sense that a second manway portal cover with an aperture having a second size could be substituted for a first manway portal cover having a first size by simply replacing the first manway portal cover with the second manway portal cover. In this way, if a larger or smaller aperture is required (or if more than one aperture is required), manway portal covers may be simply exchanged one for another without any substantial labor costs, safety concerns, or excessive downtime.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features, aspects, and advantages of the present disclosure will become better understood by reference to the following detailed description, appended claims, and accompanying figures, wherein elements are not to scale so as to more clearly show the details, wherein like reference numbers indicate like elements throughout the several views, and wherein:

FIG. 1 shows a front view of a manway portal cover apparatus oriented to substantially cover a manway portal of a pressure vessel;

FIG. 2 shows a side view of the manway portal cover apparatus of FIG. 1 as cut along line A-A;

FIG. 3 shows a close-up view of a portion of a manway portal cover apparatus that includes a groove for attaching a sealing aid.

FIG. 4 shows a front view of a manway portal cover apparatus that includes an attachment member, the cover apparatus being oriented to substantially cover a manway portal of a pressure vessel;

FIG. 5 shows a side view of the manway portal cover apparatus of FIG. 4 as cut along line B-B;

FIG. 6 shows a front view of a manway portal cover apparatus that includes only two engagement members, the cover apparatus being oriented to substantially cover a manway portal of a pressure vessel;

FIG. 7 shows a side view of the manway portal cover apparatus of FIG. 6 as cut along line C-C;

FIG. 8 shows a side view of a manway portal cover apparatus that includes a plurality of attachment rods, the cover apparatus being oriented to substantially cover a manway portal of a pressure vessel;

FIG. 9 shows a front view of a manway portal cover apparatus that includes a plurality of attachment ports and an attachment member, the cover apparatus being oriented to substantially cover a manway portal of a pressure vessel; and

FIG. 10 shows a side view of the manway portal cover apparatus of FIG. 9 as cut along line D-D.

DETAILED DESCRIPTION

FIGS. 1-2 show a preferred embodiment of a cover apparatus 10 for providing access to a pressure vessel. The term “pressure vessel” is defined herein as any vessel that maintains or operates at an average gauge pressure that is greater than an ambient pressure at a particular elevation relative to sea level. Thus, a tank that operates at an average gauge pressure greater than zero pounds per square inch gauge (psig) at sea level would be considered a “pressure vessel” as defined herein. The apparatus 10 includes a plate 12 having a first surface 14, a second surface 16, an aperture 18 extending through the plate 12, and a plurality of engagement members 20. The engagement members 20 are located along the second surface 16 of the plate 12. The plate 12 is preferably ASME certified, and if certified, such certification is made after the aperture 18 is formed in the plate 12. The cover apparatus 10 may be used to replace a conventional manway cover used with a pressure vessel so that one or more additional access points (e.g., apertures) are made available for operational access to the interior of a pressure vessel without the need to physically alter the pressure vessel itself or any of its associated conventional structural parts. The term “operational access” is defined herein as access to the interior of a pressure vessel while the pressure vessel is in operation or otherwise pressurized above ambient pressure.

The plate 12 is shaped so that it may be maneuvered to fit through the manway portal of a pressure vessel while the plate 12 is in a first orientation, but also shaped so that the plate 12 substantially covers the manway portal of a pressure vessel while the plate is maneuvered into a second orientation (shown in FIGS. 1-2). Because of this geometry, the cover apparatus 10 may be moved to the interior of a pressure vessel and then maneuvered to substantially cover the manway portal of the pressure vessel from the inside of the pressure vessel. The plate 12 is preferably oval shaped, but many other shapes are also contemplated. A preferred geometric relationship between the cover apparatus 10 and a pressure vessel is illustrated, for example, in FIGS. 1-2. In FIG. 2, the outside shell 22 of a pressure vessel is shown relative to a manway portal 24 that is defined by a collar flange 26 that extends substantially orthogonal to the shell 22. The collar flange 26 is typically welded to the shell 22 of a pressure vessel along a rim 28 surrounding the manway portal 24. When the cover 10 is oriented as shown in FIGS. 1-2, the collar flange 26 defining the manway portal 24 prevents the cover 10 from exiting the manway portal 24 because the outside edge 30 of the cover 10 extends beyond an inner edge 32 of the collar flange 26. Preferably, a gasket, O-ring, or other sealing aid known to a person having ordinary skill in the art is attached to the second surface 16 of the cover 10 at the location substantially where the cover 10 contacts the inner edge 32 of the collar flange 26. In a particularly preferred embodiment as shown in FIG. 3, the cover 10 includes a groove 34 where a sealing aid 36 may be attached to better insure a seal between the cover 10 and the inner edge 32. The sealing aid 36 may be attached to the cover 10 using, for example, an adhesive such as contact cement glue.

The term “manway portal” is defined broadly herein to include apertures of varying sizes that are used to access a pressure vessel when such pressure vessel is not operational or otherwise pressurized. Thus, for example, a manway portal may include an aperture in a pressure vessel that is only wide enough for a human hand to fit through (e.g., an area of 16 in²).

The thickness of the plate 12 may, for example, be about 1 inch. The example of plate 12 thickness is given as an illustration only and is not meant to be limiting because the size of plate 12 may vary widely depending on the particular application for which plate 12 is used. As shown in FIGS. 1 and 4, the plate 12 preferably includes a plurality of attachment pockets 38 near the aperture 18. The pockets 38 are preferably threaded and extend partially into the plate 12 for attaching an object to the plate along the aperture 18. Such object may include, for example, a flange including a sensor that is exposed to the interior of the pressure vessel via the aperture 18 of the cover apparatus 10. In an embodiment that does not include pockets 38, an example of an object attached along the aperture 18 may include, for example, a specifically sized coupling that may be welded to the second surface 16 of the cover 10 whereby the coupling may be further attached to a separate device (e.g., a monitoring device, an inlet port, a sampling port for drawing samples from the interior of the pressure vessel). Thus, in various embodiments, the cover apparatus 10 allows operational access to the interior of the pressure vessel without the necessity of creating an aperture in the pressure vessel itself or the manway cover previously used with the pressure vessel. This is important because the vast majority of conventional manway covers are ASME certified based on failure tests. If an aperture were created in a conventional manway cover after such certification, the ASME certification for that manway cover would become meaningless because the fundamental structure of the manway cover would have been altered, rendering the fail test results unreliable. Creating a new aperture in a pressure vessel itself is also undesirable because of dangers associated with welding and other aperture creation techniques as well as the cost for the work and costs and delays associated with extended downtime of the pressure vessel. By replacing conventional manway covers with the cover apparatus 10 or other embodiments of the disclosure described herein, the expensive, dangerous, and time consuming task of creating new apertures in conventional pressure vessels to gain operational access to such pressure vessels is virtually eliminated.

In preferred embodiments, the engagement members are spaced away from the center of the second surface of the plate so that space is maximized for a potentially large object to be attached to the plate along the second surface. What is defined as a “large” object is relative to the size of the cover apparatus itself and is understood to a person having ordinary skill in the art. Because objects such as sensors and other machinery or modules to be attached to the plate 12 may change over time in size, shape, and number, different sized apertures may be required through time. Additionally, additional numbers of apertures in a particular plate 12 may be required. An advantage of the cover apparatus 10 and other embodiments described herein is that a first cover apparatus with a first aperture having a first size may quickly, easily, relatively safely, and inexpensively be substituted for a second cover apparatus with a second aperture having a second size. Similarly, a first cover apparatus having a lesser number of apertures may quickly, easily, relatively safely, and inexpensively be substituted for a second cover apparatus having a greater number of apertures.

With regard to the cover apparatus 10, the size and shape of the aperture 18 may vary depending on the particular application that the cover apparatus 10 is used for. The position of the aperture 18 along the plate 12 may vary, but the aperture 18 is preferably substantially centered along the plate 12 as shown in FIG. 1. The cover 10 is preferably made of metal or a metal alloy such as, for example, steel, iron, or aluminum. In an exemplary application, the long radius (R_(L)) of the plate 12 is about 16 inches, and the short radius (R_(S)) of the cover preferably is about 12 inches. Although specific size ranges are given above for the plate 12, sizes may vary widely from application to application because pressure vessels come in a wide variety of sizes.

There may be as few as two engagement members 20 along the second surface 16 of the plate 12 as shown in FIGS. 6-7. The preferred embodiment shown in FIGS. 1-2 includes six engagement members 20. The engagement members 20 shown with the embodiment of FIGS. 1-5 include a plurality of extension members 40. Each extension member 40 includes an aperture 42. In a preferred embodiment, the apertures 42 are threaded orifices. The extension members 40 resemble an upside-down three-dimensional letter “U” with an aperture at the base of the “U”. As an example, the height of an extension member 40 may be about 3 inches, the width of an extension member may be about 1 inch, and the thickness of an extension member may be about 0.25 inches. The extension members are preferably made of steel, iron, or other high tensile strength material known to a person having ordinary skill in the art.

The engagement members 20 are for engaging with one or more attachment members 44 so that the cover 10 may be held in place against the inner surface of the pressure vessel at least until the pressure vessel is pressurized. After the pressure vessel is pressurized, the pressure in the pressure vessel will theoretically do some or most of the work keeping the cover 10 in place against the inside surface of the pressure vessel. However, it is preferred that the attachment members 44 hold the cover apparatus 10 in place substantially continuously in the event of pressure loss (intentional or unintentional) in the pressure vessel. FIGS. 4-5 show an example of an attachment member 44 attached to an engagement member 20. The attachment member 44 includes a bolt 46 including a first end 48 and a second end 50 and a retainer member 52 including an aperture 54. If all attachment members 44 were shown in FIG. 4, there would be six bolts 46 and six retainer members 52. A preferred embodiment of this disclosure includes one or more attachment members 44.

As shown in FIGS. 3-5, the bolt 46 may be placed through the aperture 54 of the retainer member 52 and the second end 50 of the bolt 46 may be attached to the aperture 42 of an extension member 40. The retainer member 52 may be oriented to overlap an outer edge 56 of the collar flange 26, and the bolt 46 may be tightened. When two or more attachment members 44 are attached to two or more engagement members 20 in this way, the cover may be held in place against the outer edge 56. FIGS. 6-7 show, for example, an embodiment of a cover apparatus 58 that includes only two of the engagement members 20 for attachment to two of the attachment members 44. The bolt 46 is preferably made of steel, iron, or other high tensile strength material known to a person having ordinary skill in the art. The first end 48 of the bolt 46 may be various shapes and have various features (e.g., Phillips head indentation) known to a person having ordinary skill in the art. The retainer member 52 is preferably made of steel, iron, or other high tensile strength material known to a person having ordinary skill in the art.

FIG. 5 also shows a balancing member 60. A preferred embodiment of this disclosure includes a plurality of balancing members 60 for balancing stresses along the retainer members 52 as the bolts 46 are tightened. The physical relationship shown in FIG. 5 between the outer edge 56 of the collar flange 26, the retainer member 52, and the balancing member 60 shows how the balancing member 60 helps to distribute force from the retainer member 52 to both the outer edge 56 of the flange collar 26 and the balancing member 60. The balancing member 60 may be a separate object inserted between the second surface 16 of the plate 12 or, alternatively, the balancing member 60 may be attached (e.g., by welding) to the second surface 16 of the plate 12. In one embodiment shown in FIG. 10, a retainer member 62 includes a retaining cap 64 and a side extension 66 attached thereto, wherein the side extension is attached to and oriented orthogonal to the retaining cap 64 so that a separate balancing member 60 is effectively replaced by the side extension 66 and, therefore, a separate balancing member 60 is unnecessary. The retaining cap 64 is preferably substantially identical to the retainer member 52. The balancing member 60 preferably is made of steel, iron, or other high compression strength material known to a person having ordinary skill in the art.

In a related embodiment, FIG. 8 shows a cover apparatus 68 that includes a plurality of engagement members 70. The plurality of engagement members 70 include a plurality of rods 72 that are preferably threaded at a first end 74 of the rods 72. The rods 72 are preferably welded to the second surface 16 of the plate 12, but a wide range of other ways of attaching the rods 72 to the plate 12 are known to persons having ordinary skill in the art. Alternatively, the rods 72 may be removably attachable to the plate, for example, by threading both ends of the rods 72 so that the rods 72 may be screwed into the plate 12 shown in FIGS. 9-10. The rods are preferably made of substantially the same material as the plate 12. The cross-sectional shape of the rods 72 may be polygonal, circular, or a combination of straight and curved edges. The cover apparatus 68 shown in FIG. 8 may be attached to a pressure vessel using a plurality of attachment members 76. The plurality of attachment members 76 includes sets, each set including a retainer member 52 and a cap member 78. After the cover apparatus 68 is oriented within the pressure vessel for covering the manway portal 24 of the pressure vessel, each retainer member 52 may be oriented so that the individual rods 72 extend through the apertures 54 of the retainer members 52. A separate cap member 78 may be attached to the first end 74 of each of the rods 72. The retainer members 52 may be oriented to overlap the outer edge 56 of the collar flange 26, and the cap members 78 may be tightened along the rods 72. When two or more attachment members 76 are attached to two or more engagement members 70 in this way, the cover may be held in place against the inner edge 32.

As with the embodiments including the cover apparatus 10, embodiments including the cover apparatus 68 may also include one or more balancing members 60. Additionally or alternatively, the embodiment including the cover apparatus 68 may also include one or more retainer members 62.

In another embodiment. FIGS. 9-10 show a cover apparatus 80 that includes a plurality of engagement members 82. The plurality of engagement members 82 includes a plurality of attachment ports 84 that extend partially into the second surface 16 of the plate 12. The attachment ports 84 are preferably threaded. The attachment ports 84 may be attached to the attachment members 44 in the manner that the attachment members 44 were attached to the engagement members 20 discussed above. More specifically, the bolt 46 may be placed through the aperture 54 of the retainer member 62 and the second end 50 of the bolt 46 may be attached to one of the attachment ports 84. The retainer member 62 may be oriented to overlap the outer edge 56 of the collar flange 26, and the bolt 46 may be tightened. When two or more attachment members 44 are attached to two or more engagement members 82 in this way, the cover apparatus 80 may be held in place against the inner edge 32.

The disclosure further provides for a cover apparatus that includes different types of engagement members. For example, a cover apparatus may include at least one extension member 40 and at least one attachment port 84. In another example, a cover apparatus may include at least one attachment port 84 and at least one attachment rod 72. In yet another example, a cover apparatus may include at least one extension member 40 and at least one attachment rod 72.

Other embodiments of this disclosure include a method for adding an access point to a pressure vessel without the necessity of creating a new aperture in the pressure vessel itself or any prior associated manway portal cover. The method includes a step 110 of providing a cover apparatus substantially similar or identical to the cover apparatus 10, the apparatus including a plate, a first surface, a second surface, an aperture, and a plurality of engagement members. The method further includes a step 112 of inserting the cover apparatus through a manway portal of a pressure vessel such that the second surface of the cover apparatus faces outward from the manway portal. The method also includes a step 114 of attaching one or more attachment members to a plurality of engagement members such that the second surface of the cover apparatus substantially sealingly covers the manway portal. The method may further include a step 116 of orienting the attachment members so that the attachment members overlap an outer edge of a collar flange that surrounds the manway portal. Preferably, the method further includes a step 118 of attaching an object to the cover apparatus along the aperture wherein the object is exposed to the interior of the pressure vessel via the aperture.

Advantages of these and other embodiments of the disclosure discussed herein include an apparatus that may be rapidly swapped with a conventional manway portal cover for the purpose of gaining operational access to a pressure vessel in very little time. For example, if a chemical plant needs to add an access point to a chemical reactor tank or storage tank, a conventional manway cover could be swapped for an embodiment of a cover described herein. Thus, there would be no need to stop storage or processing for an extended period of time in order to alter the tank itself.

Another advantage of the embodiments disclosed herein includes an apparatus and method that eliminate safety issues and related liability, particularly if the pressure vessel typically contains hazardous materials such as, for example, flammables, corrosives, and/or oxidizers. For example, if an aperture were created in the tank during downtime, such aperture would probably be formed using welding techniques or other heat generating techniques known to a person having ordinary skill in the art. Such heat generating techniques are inherently dangerous in and of themselves creating increased injury concerns for workers (employed or contracted on site). Moreover, if flammable or oxidizable material residue remains in the tank during such work, the risk of injury substantially increases even further. This disclosure offers various embodiments of desirable alternatives that bypass the need for creating apertures in the tank itself. Conventional manway covers could simply be replaced by an embodiment of a manway cover described herein with no necessity for welding or any other work to be done on the tank itself.

Yet another advantage of the embodiments disclosed herein includes a cover apparatus and method that eliminates the expensive labor costs of paying a skilled worker (e.g., a welder) to create an access point in a pressure vessel. The endeavor of gaining operational access to a pressure vessel would be simplified by the mere substitution of a manway portal cover described herein for a conventional manway portal cover.

Another advantage of the embodiments disclosed herein includes a cover apparatus that is flexible in the sense that a second manway portal cover with an aperture having a second size could be substituted for a first manway portal cover having a first size by simply replacing the first manway portal cover with the second manway portal cover. In this way, if a larger or smaller aperture is required (or if more than one aperture is required), manway portal covers may be simply exchanged one for another without any substantial labor costs, safety concerns, or excessive downtime.

The foregoing description of preferred embodiments for this disclosure has been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the disclosure to the precise form disclosed. Obvious modifications or variations are possible in light of the above teachings. The embodiments are chosen and described in an effort to provide the best illustrations of the principles of the disclosure and its practical application, and to thereby enable one of ordinary skill in the art to utilize the disclosure in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the disclosure as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled. 

1. A cover apparatus for providing access to a pressure vessel, the apparatus comprising a plate dimensioned to fit through a manway portal of a pressure vessel and to substantially sealingly engage with the pressure vessel so that the plate substantially covers the manway portal from the interior of the pressure vessel, the plate including a first surface, a second surface, an aperture located through the plate, and a plurality of engagement members along the second surface of the plate, the plurality of engagement members for engaging with an attachment member that is capable of holding the second surface of the plate against an inner surface of the pressure vessel at least until the pressure vessel is pressurized.
 2. The apparatus of claim 1 further comprising a plurality of attachment members that are removably attachable to the plurality of engagement members and that may be oriented to overlap an outer edge of a collar flange surrounding the manway portal at two or more points along the outer edge, wherein the plate may be held in place substantially covering the manway portal of the pressure vessel by attaching the attachment members to the engagement members and orienting the attachment members such that the attachment members overlap the outer edge of the collar flange.
 3. The apparatus of claim 1 further comprising a plurality of attachment pockets that extend partially into the plate along the second surface of the plate near the aperture, the plurality of attachment pockets for attaching an object to the plate along the aperture.
 4. The apparatus of claim 1 wherein the aperture is located substantially at the center of the second surface.
 5. The apparatus of claim 1 further comprising an object substantially sealingly attached along the aperture of the plate, wherein the object includes a sensor exposed to the interior of the pressure vessel.
 6. A pressure vessel comprising the cover apparatus of claim
 1. 7. The apparatus of claim 2 wherein the plurality of engagement members further comprises an extension member extending from the second surface of the plate, the extension member including an aperture.
 8. The apparatus of claim 2 wherein the plurality of engagement members further comprises an attachment port extending partially into the second surface of the plate.
 9. The apparatus of claim 2 wherein the plurality of engagement members further comprises an attachment rod extending orthogonally from the second surface of the plate.
 10. The apparatus of claim 7 wherein at least one of the attachment members further comprises a bolt including a first end and a second end, and a retainer member including an aperture, wherein the apparatus may be attached to the pressure vessel at least in part by extending the bolt through the aperture of the retainer member, orienting the retainer member such that a portion of the retainer member overlaps the outer edge of the collar flange, and attaching the second end of the bolt to the aperture of the extension member.
 11. The apparatus of claim 10 further comprising a balancing member oriented between the retainer member and the second surface of the plate, wherein the retainer member may be oriented to overlap the balancing member while the retainer member also overlaps the outer edge of the collar flange, wherein the balancing member is capable of distributing a force from the retainer member to both the outer edge of the collar flange and the balancing member.
 12. The apparatus of claim 8 wherein the attachment member further comprises a bolt including a first end and a second end, and a retainer member including an aperture, wherein the apparatus may be attached to the pressure vessel at least in part by extending the bolt through the aperture of the retainer member, orienting the retainer member such that a portion of the retainer member overlaps the outer edge of the collar flange, and attaching the second end of the bolt to the attachment port.
 13. The apparatus of claim 12 further comprising a balancing member oriented between the retainer member and the second surface of the plate, wherein the retainer member may be oriented to overlap the balancing member while the attachment member also overlaps the outer edge of the collar flange, wherein the balancing member is capable of distributing a force from the retainer member to both the outer edge of the collar flange and the balancing member.
 14. The apparatus of claim 9 wherein the attachment members further comprise a retainer member and a cap member, each retainer member including an aperture, whereby the apparatus may be attached to the pressure vessel at least in part by placing the retainer member along the rod such that the rod is exposed through the aperture of the retainer member, orienting the retainer member such that a portion of the retainer member overlaps the outer edge of the collar flange, and attaching the cap member to the end of the rod.
 15. The apparatus of claim 9 wherein the rods are removably attachable to the plate.
 16. The apparatus of claim 14 further comprising a balancing members oriented between the retainer member and the second surface of the plate, wherein the retainer member may be oriented to overlap the balancing member while the retainer member also overlaps the outer edge of the collar flange, wherein the balancing member is capable of distributing a force from the retainer member to both the outer edge of the collar flange and the balancing member.
 17. The apparatus of claim 14 wherein the cap member comprises a threaded nut and wherein the rod is at least partially threaded.
 18. A method for adding an access aperture to a pressure vessel without the necessity of creating a new aperture in the pressure vessel or associated manway portal cover, the method comprising the steps of: (a) providing a cover apparatus for providing access to a pressure vessel, the apparatus comprising a plate dimensioned to fit through a manway portal of a pressure vessel and to substantially sealingly engage with the pressure vessel so that the plate substantially covers the manway portal from the interior of the pressure vessel, the plate including a first surface, a second surface, an aperture located through the plate, and a plurality of engagement members along the second surface of the plate, the plurality of engagement members for engaging with an attachment member that is capable of holding the second surface of the plate against an inner surface of the pressure vessel at least until the pressure vessel is pressurized; (b) inserting the plate through the manway portal of the pressure vessel such that the second surface substantially faces out through the manway portal; (c) attaching a plurality of attachment members to the plurality of engagement members such that the manway portal is substantially sealingly obstructed by the cover apparatus.
 19. The method of claim 18 further comprising the step of orienting the attachment member so that the attachment member overlaps an outer edge of a collar flange surrounding the manway portal of the pressure vessel at two or more locations along the outer edge of the collar flange.
 20. The method of claim 18 further comprising the step of attaching an object to the cover apparatus whereby the object is exposed to the interior of the pressure vessel after the manway portal becomes obstructed by the cover apparatus. 